Their builds are designed so that people who don't have experience can work on them, under the supervision of people that do have experience. 

The initial repair fee is designed to stop the tenants from clogging toilets sinks or showers with hair,grease or paper etc. 

., finding a lender to get a constructions loan, finding an architect to design 4-plex, dealing w/ city bureaucracy moving forward, etc.

(Anecdotally, the typical response is likely to be "Oh, no issues for Illinois, except that Landlord must designate wither the security deposit will be held in an interest bearing account or a non-interest bearing account", or some other very minor comment.) 

Renovation and my keen sense of design.

(This comment was composed and designed to reflect the the current thoughts of the commenter and was not meant to insult the innocent or their dog.

@Eric Ippolito  first it takes Capital to fund the due diligence process and bring the project to shovel ready but the following steps are free and are done by you to determine feasibility.Check with the city or county to determine what is required for all approvals including site plan and building permits, proffers, water/sewer tap fees, bonding requirements, inspections and CO process and time frame for all approvals.You also need to check with the utility companies and get an idea of availability and cost estimates from them for water, sewer, power, gas, cable, installation and connection requirements, tap fees, hookup charges, transformer location and relocation, power line and power pole relocation issues.Check to see if you have to install any manholes,fire hydrants, curb, gutter, sidewalks, street signs, street lighting any specific street design or access requirements,.Check DOT requirements for access, stop lights and permits, traffic studiesDWQ requirements for permits, permit fees, time framesThis is a broad overview of the process and your civil engineer can handle all of this but it's good for you to know exactly what's required.

The BRRRR method is designed for this type of a scenario. 

I completely designed and renovated the property converting to two bi-level apartments doing all design and construction work myself.

There are some softwares out there that are inexpensive and are specifically designed for small portfolios.When you add in the online rent collection and tracking of expenses and some other features they are almost always worth the cost in my opinion.